Induction watthour meter potential coil mounting

ABSTRACT

The potential coil of an induction watthour meter is encapsulated in an electrically insulating resinous material and mounted on the winding leg of the potential electromagnetic or core of the meter. The lower end of the encapsulated coil which is closest to the voltage pole face is provided with plastic bosses which contact the bottom pole piece of the potential core. The upper end of the coil is movably held by a spring member between the top of the encapsulated coil and a recess in the watthour meter frame, the potential core being mounted on such meter frame. Alternatively, a spring member is mounted on the top of the potential core pressing against the top of the encapsulated coil.

[451 Feb. 12,1974

United States Patent [1 1 Loika, Jr.

Primary Examiner-Alfred E. Smith INDUCTION WATTHOUR METER POTENTIAL COIL MOUNTING Attorney, Agent, or Firm-Francis X. Doyle; Volker R. Ulbrich [75] Inventor: Alexander Loika, Jr., Somersworth,

[57] ABSTRACT The potential coil of an induction watthour meter is General Electric Company Aug. 23, 1972 Appl. No.: 283,195

[73] Assignee:

encapsulated in an electrically insulating resinous ma- Filed:

the bottom pole piece of the potential core. The upper 1 0 G O QML um 21 55 Field f Search... 324/]37, 138; 336/197, 205; end of the coil is movably held by a spring member 335/224 between the top of the encapsulated coil and a recess in the watthour meter frame, the potential core being [56] mounted on such meter frame. Alternatively, a spring member is mountedon the top of the potential core References Cited FOREIGN PATENTS OR APPLICATIONS H1971 Germany 324/137 pressing aga nst the top of the encapsulated C01].

4 Claims, 6 Drawing Figures INDUCTION WATTIIOUR METER POTENTIAL COIL MOUNTING BACKGROUND OF THE INVENTION .This invention relates to coil mounting and more particularly to a novel means of mounting the potential coil of an induction watthour meter on the potential core or electromagnet to allow expansion of the potential coil;

In induction type watthour meters, a potential electromagnet and a current electromagnet are provided on opposite sides of a slot or opening in the meter frame in which moves the induction disc or rotor. The potential electromagnet is usually formed from a plurality of E-shaped core laminations which are secured together such as, for example, by riveting. The potential or voltage winding is mounted on the center or winding leg with the lower end of such winding leg, which is remote from the yoke, providing a voltage flux pole. The potential or voltage coil is usually encapsulated in an electrically insulating resin to improve its dielectric strength. The potential coil is normally secured to the winding leg often by use of an adhesive material which is normally applied randomly between the inner opening of the encapsulated coil and the winding leg.

As is well known, all types of plastics tend to absorb moisture, especially under high humidity conditions. As moisture is absorbed, the plastic material tends to swell or expand. When a potential coil is encapsulated in a plastic material, it also has a tendency to expand from absorbed moisture, especially when used in high humidity areas. When the encapsulated coil expands, it often expands in the downward direction toward the voltage flux pole and the main air gap of the potential electromagnet. As will be understood, should the voltage coil expand into the air gap, it would affect the calibration of the induction watthour meter. In order to prevent expansion of the encapsulated potential coil from affecting the calibration of the meter, it is necessary to provide for the expansion of the coil toward the yoke of the voltage or potential-electromagnet. It is towards this end that this invention is directed.

It is, therefore, one object of the invention to provide a novel means of mounting a potential coil on a potenial electromagnet.

A still further object of this invention is to provide a novel means of mounting a potential coil on a potential electromagnet which will prevent the coil from expanding towards the voltage flux pole.

A still further object of this invention is to provide a novel means of mounting a potential coil on a potential electromagnet such that the end nearest the voltage flux pole is generally fixed while the other end is free to expand as necessary.

A still further object of this invention is to provide a novel means of mounting a potential coil on a potential electromagnet wherein the end of the coil closest to the voltage flux pole has means contacting the pole face while the opposite end is movably mounted by spring means which will allow expansion against such spring means.

SUMMARY OF THE INVENTION In carrying out this invention in a preferred form, the potential coil of an indication watthour meter is first encapsulated in an electrically insulating resinous material. The encapsulated potential coil is then assembled on the winding legof a potential electromagnet. The lower end of the encapsulated potential coil is provided with bosses which contact the pole face of the potential electromagnet. The upper or opposite end of the encapsulated coil, is movably held by a spring which may be mounted on the core or mounted in a recess in the meter frame thereby allowing the potential coil to expand in an upward direction toward the yoke of the potential electromagnet,

The invention sought to be protected will be clearly pointed out and distinctly claimed in the claims appended hereto. However, it is believed that this invention and the manner in which its various objects and advantages are obtained as well as other objects and advantages thereof will be more clearly understood by reference to the following detailed description of the present preferred embodiment, particularly when considered in the light of the accompanying drawing.

BRIEF DESCRIPTION OF DRAWING FIG. 1 is a perspective-view of an encapsulated potential coil and a potential core or electromagnet for a watthour meter assembled according to the preferred embodiment of this invention;

FIG. 2 is a partial sectional side view of the assembly shown in FIG. 1 and includes a portion of the watthour meter frame;

FIG. 3 is a perspective view of a spring member mounted in the watthour meter frame according to the preferred embodiment of this invention;

FIG. 4 is a partial front view of the potential coil and core showing a portion of this invention in greater detail;

FIG. 5 is a perspective view of the bottom pole piece of the potential core or electromagnet, and the clamp or brace used to secure the pole piece to the potential core; and

FIG. 6 is a partial, rear perspective view of the potential core and coil showing another form of spring retaining means.

DESCRIPTION OF PREFERRED EMBODIMENT This invention relates to a novel means of mounting an encapsulated potential coil on the potential core or electromagnet of an induction watthour meter. As such, induction watthour meters are well known to those skilled in the art as is shown, for example in US. Pat. No. 2,930,980. Therefore, for clarity and understanding of this invention, only the encapsulated potential coil and the potential-electromagnet with the necessary portion of the frame will be shown and described. It is believed that the scope of this invention will be more clearly understood by such description.

Referring now to the drawing wherein like numerals are used to indicate like parts throughout, and referring specifically to FIGS. 1 and 4 thereof, there is shown a plurality of views of the assembly of an encapsulated potential coil and the potential core or electromagnet such as is utilized in an induction watthour meter. The potential electromagnet 10 is comprised of a plurality of substantially E-shaped laminations having a central winding leg 12 which ends in a voltage flux pole 14 in a manner well understood by those skilled in the art. The lower ends of outer legs 16 form air gaps 18 with the voltage flux pole l4 as'is well understood. In the form shown, the plurality of laminations are securely fastened by means of rivets 20, 20a.

A bottom pole piece 22, shown in perspective view in FIG. 5, is secured to the outer legs 16 by a clamp or brace 24, also shown in perspective view in FIG. 5. The pole piece 22 is secured to clamp 24 by rivets 26, while clamp 24 is secured to outer legs 16 by the rivets 20.

An encapsulated potential coil 28 is mounted on winding leg 12 as clearly shown in FIGS. 1 and 4. In the preferred form of this invention, the lower end 30 adjacent voltage flux pole 14 is. provided with bosses 32 which contact the upper surface 34 of pole piece 22, as is indicated by the dotted lines 32a in FIG. 5.

In the preferred embodiment of this invention, the bosses 32 are formed integrally with the encapsulated material of potential coil 28. Of course, it will be understood that bosses 32 should be of a non-conductive material. Obviously, they could be provided after the encapsulation of potential coil 28, and of a material other than that used to encapsulate potential coil 28.

However, as will be understood, it is relatively easy to form such bosses 32 during the encapsulation of the potential coil 28.

As earlier discussed, when the resinous material encapsulating potential coil 28 absorbs moisture, the coil tends to expand. By the provision of bosses 32 on potential coil 28 so that such bosses 32 on the lower end 30 of the coil contact the upper surface 34 of pole piece 22, the coil 28 will be forced to expand in an upward direction toward the yoke portion 36 f potential electromagnet 10. However, because of vibration and other movement of the electromagnet 10, the coil 28 has a tendency to move or wobble on winding leg 12.

To prevent such movement in the preferred embodiment of this invention, a spring member 38, best shownin FIGS. 2 and 3, is provided. Spring member 38 is a leaf spring which is mounted in a recess 40 of the watthour meter frame 42, only a portion of such frame being shown in the drawing. As is shown in FIGS. 2 and 3, the assembled potential core and coil 28 are mounted on frame 42 by a plurality of rivets or bolts 44 which extend through frame 42 and potential core 10. If bolts 44 are used, nuts 46 are provided which are threaded on bolts 44, as shown.

The recess 40 is provided in frame 42 positioned immediately above the upper end 48 of potential coil 28. As is apparent from the drawing, metal projections 40a are provided on each side of recess 40 and spring 38 is placed in projections 40a of recess 40 with spring ends 50 secured in the edges of such projections 40a. The. center portion 52 of spring 38 is bowed downwardly in contact with upper end 48 of potential coil 28. As will be apparent, spring 38 will assert a downward force on potential coil 28, forcing bosses 32 into positive contact with the upper surface 34 of pole piece 22. This will prevent any undesired movement of the potential coil 28 on winding leg 12. Any expansion of the encapsulated potential coil 28, due either to temperature or moisture adsorption will be in an upward direction, deflecting spring 38. The bosses 32 will prevent expansion upper end 48 of potential coil 28. As shown in FIG. 6,

the rivets 20b in potential core 10 extend rearwardly toward frame 42 (not shown in FIG. 6). The rivets 20b receive edges 50a of leaf spring 38a, as shown. The center portion 52a of spring 38a is bowed downwardly in contact with the upper end 48 of potential coil 28. As will be understood leaf spring 38a will function the same as spring 38, preventing any undesired movement of the potential coil 28 on winding leg 12.

While there has been shown and described the present preferred embodiments of the invention, it will be understood that various changes may be made in specific details thereof without departing from the spirit and scope of the invention. For example, different shapes of potential coils may be utilized and different types of springs may be used as desired. It is intended by the claims appended thereto to include all such changes as are within the spirit and scope of the invention hereinabove described.

What is claimed as new and which it is desired to secure by Letters Patent of the United States is:

1. A potential coil and electromagnet assembly for an induction watthour meter, said coil being encapsulated in a resinous material, said electromagnet having a central winding leg and a pair of outer legs, said central winding leg having a flux pole at one end and said outer legs having ends providing air gaps with said flux pole, a pole piece mounted on said ends of said outer legs and extending under said flux pole, said potential coil mounted on said central winding leg, the end of said potential coil nearest said air gaps having rigid bosses which contact the upper surface of said pole piece to prevent movement of said coil toward said air gap, and spring means contacting the other end of said potential coil to force said bosses into positive contact with said upper surface of said pole piece.

2. A potential coil and electromagnet assembly for an induction watthour meter as set forth in claim 1, in which said electromagnet is secured to a watthour meter frame, a recess provided in said frame adjacent the yoke portion of said electromagnet and said spring means being a spring mounted in said recess and contacting the other end of said potential coil.

3. A potential coil and electromagnet assembly for an induction watthour meter as set forth in claim 1, in which said spring means contacting the other end of said potential coils is in the form of a leaf spring having its ends secured to rivets in said potential electromagnet.

4. A potential coil and electromagnet assembly for an induction watthour meter as set forth in claim 1, in which said spring means contacting the other end of said potential coil is in the form of a leaf spring having its ends secured to a portion of the frame of the watthour meter. 

1. A potential coil and electromagnet assembly for an induction watthour meter, said coil being encapsulated in a resinous material, said electromagnet having a central winding leg and a pair of outer legs, said central winding leg having a flux pole at one end and said outer legs having ends providing air gaps with said flux pole, a pole piece mounted on said ends of said outer legs and extending under said flux pole, said potential coil mounted on said central winding leg, the end of said potential coil nearest said air gaps having rigid bosses which contact the upper surface of said pole piece to prevent movement of said coil toward said air gap, and spring means contacting the other end of said potential coil to force said bosses into positive contact with said upper surface of said pole piece.
 2. A potential coil and electromagnet assembly for an induction watthour meter as set forth in claim 1, in which said electromagnet is secured to a watthour meter frame, a recess provided in said frame adjacent the yoke portion of said electromagnet and said spring means being a spring mounted in said recess and contacting the other end of said potential coil.
 3. A potential coil and electromagnet assembly for an induction watthour meter as set forth in claim 1, in which said spring means contacting the other end of said potential coils is in the form of a leaf spring having its ends secured to rivets in said potential electromagnet.
 4. A potential coil and electromagnet assembly for an induction watthour meter as set forth in claim 1, in which said spring means contacting the other end of said potential coil is in the form of a leaf spring having its ends secured to a portion of the frame of the watthour meter. 